1. Field of the Invention
The present invention relates to a biaxially stretched bottle in which a carrying handle injection molded integrally with a preform on the side of a lower neck portion thereof is applied as-formed as a handle of the bottle.
2. Background Art
A biaxially stretched bottle represented by a bottle made of polyethylene terephthalate, so-called PET bottle is formed by stretch blowing an injection molded preform from a lower portion of a neck portion thereof to a bottom portion thereof in length and width so as to have a thin wall. From these reasons, unlike a thick-wall bottle formed by blowing a parison made by extrusion molding, it is considered infeasible that a body portion thereof is transformed in part to a handle on blow-molding using a mold, or as described in U.S. Pat. No. 3,441,172, a carrying handle is formed integrally by pressing on a shoulder portion of a bottle.
Therefore, usually when a bottle is stretch blow molded, a handle is inserted into a lower neck portion of a preform, or a handle separately injection molded is inserted into a blow mold to attach to the side of a body portion thereof.
In some cases, apart from integration of a handle and a bottle by inserting, a handle is attached to a bottle by using fitting means after a bottle is formed. However, in both cases, compared with common method of production of a bottle having no handle, facilities cost is increased because a preform and a handle have to be made separately and problems remain unsolved with respects to yield.
These problems can be solved by forming a handle integrally with a preform. However, there still remains other problems in which the position where a handle is formed is limited within a lower neck portion, the shape of which does not change on forming of a bottle, and the shape of a handle is also limited because as mentioned earlier, on stretch blow molding a preform is stretched along its axis except for a neck portion.
For example, the handle described in WO82/02369 is belt-shaped and integrally formed horizontally on one side of a lower neck portion of a preform at the same time when the preform is injection molded, and has elliptical holes to enable plural fingers to be inserted thereinto. Accordingly, this is only a simple handle for carrying a bottle, rather than a handle for supporting a bottle firmly in a lateral portion.
A bottle having such a simple carrying handle is also described in U.S. Pat. No. 4,372,454. However, the known carrying handle is made thick to have a certain strength, and finds difficulty in bending because, unstretched together with a neck portion it is hard and lacks in flexibility, especially when a material resin is polyethylene terephthalate (PET). The carrying handle would not bend vertically even when provided with a groove for folding, and a bottle hangs obliquely.